Gripper construction for duplicators



Dec. 23, 1958 w. R. FOWLIE ET AL 2,865,289

GRIFPER CONSTRUCTION FOR DUPLICATORS I Filed Oct. 5, 1956 3 Sheets-Sheet1 frail INVENTORS Wallace B. fbwlz'd John L. Tregag b fdgarli. P115015 QW KZ/WMM fliiornags Dec. 23, 1958 I w. R. FOWLIE ETAL 7 2,865,289

GRIPPER CONSTRUCTION FOR DUPLICATORS Filed 001;. 3, 1956 3 Sheets-Sheet2 was INVENTORSI Zlfallace 2. fbwlze Dec. 23, 1958 w. R. FOWLIE ET AL2,365,239

GRIPPER CONSTRUCTION FOR DUPLICATORS 3 Sheets-Sheet 3 Filed 0:31;. 3,1956 INVENTORS ZZ/azllacc 2. 1591111123 Unite States Patent GRIPPERCUNSTRUCTIUN FOR DUPLICATORS Wallace R. Fowlie, North Riverside, John L.Tregay,

Broadview, and Edgar H. Du Bois, Chicago, 111., assignors to A. B. DickCompany, Niles, Ill., a corporation of Illinois Application October 3,1956, Serial No. 627,529

.5 Claims. (CL 101-409) This invention relates to duplicators or otherprinting machines, and pertains particularly to gripper constructionsfor securing the leading edges of paper sheets to a printing cylinder.

One object of the present invention is to provide a new and improvedgripper construction having stop means whereby the leading edge portionof the sheet to be printed is accurately and positively located andpositioned with respect to the printing cylinder, so that the printedmatter will be accurately registered on the sheet with respect to theleading edge thereof.

A further object is to provide a new and improved gripper constructionin which sheet-guiding elements are secured to the gripper fingers andare arranged to extend at an acute angle thereto to define an acutelyangled crotch therebetween, so that the sheets to be printed will slidealong the guiding elements into the crotch and will be positivelylocated therein.

It is another object to provide a new and improved gripper constructionhaving individually fiexible and resilient gripper fingers, with stopfingers disposed therebetween and having portions extending at an acuteangle to the gripper fingers to define a paper receiving crotchtherebetween.

A further object is to provide a new and improved gripper constructionin which the gripper fingers are moved against an anvil portion on thecylinder and are flexed a controlled amount so as to clamp thesuccessive paper sheets between the fingers and the anvil portion.

It is a further object to provide a new and improved gripperconstruction which is highly eifective yet is reasonably simple and lowin cost.

Further objects and advantages of the present inven- I tion will appearfrom the following description, taken with the accompanying drawings, inwhich:

Fig. 1 is a diagrammatic side elevational view of a three cylinderprinting machine equipped with a gripper mechanism constituting anillustrative embodiment of the present invention.

Fig. 2 is an enlarged side elevational view showing the grippermechanism.

Figs. 3, 4 and 5 are fragmentary enlarged cross sectional views showingsuccessive positions of the grippers.

Fig. 6 is a fragmentary perspective view showing the gripper mechanism,as embodied in the impression cylinder of the printing machine shown inFig. 1.

Fig. 7 is a fragmentary perspective view, similar to Fig. 6 but withportions of the impression cylinder broken away.

Fig. 8 is an exploded view showing components of the gripper mechanism.

It will be understood that the present invention may be applied to alltypes of duplicators and printing machines. Thus, it is merely by way ofexample that the drawings illustrate a three cylinder offset printingmachine 10 having a plate or master cylinder 12, a blanket or oifsetcylinder 14, and an impression cylinder 16. The master cylinder 12 isadapted to hold a master print- 2,865,289 Patented Dec. 23, 1958 setcylinder 14 and the impression cylinder 16.

The printing machine or duplicator 10 is provided with a grippermechanism 18 whereby the leading edges of the successive sheets arecarried into the nip between the offset and impression cylinders 14 and16. In this case, the gripper mechanism 18 is mounted on the impressioncylinder 16.

It will be seen that the impression cylinder 16 has a cylindricallycurved outer surface 20 which is adapted to receive and back up thepaper sheets as they are printed by the offset cylinder 14. Thecylindrical portion 20 of the cylinder 16 is interrupted by a gap orslot 22 in the cylinder. At one end of the cylindrical surface 20,adjacent the gap 22, the cylinder 16 is provided with a longi tudinallyextending anvil portion 24 against which the leading edges of the papersheets are adapted to be clamped. It will be seen that the anvil portionangles inwardly or recedes from the curve of the cylindrical portion 20.The anvil portion 24 is interrupted by a plurality of slots or notches26, for a purpose that will be described in greater detail shortly.

Gripper elements 28 are adapted to engage the anvil portion 24 so as toclamp the paper sheets to the impression. cylinder 16. It will be seenthat the gripper elements 28 are swingable toward and away from theanvil portion 24, between the open and closed portions of Figs. 3 and 4.

The grippers 28 may be varied in construction, but in this case theytake the form of thin, flat blades or fingers secured to a gripper shaft30 which is rotatably mounted on the impression cylinder 16. Theillustrated grippers 28 are made of spring sheet metal and are flexibleand resilient. In this case, the gripper shaft 30 is square in crosssection. The gripper blades 28 are clamped or otherwise secured againstone fiat face 32 of the shaft 38. From Figs. 6 and 8, it will be seenthat the grippers 28 are formed in pairs on two sheet metal parts 34. Oneach part 34, the gripper blades 28 extend laterally from a body portion36 which is secured to the gripper shaft 30 by bolts 38 or othersuitable fasteners. Thus, the sheet metal parts 34 are generallyC-shaped.

It will be understood that the successive sheets to be printed are fedto the impression cylinder 16 when the grippers 28 are open, asillustrated in Fig. 3. The sheets may be fed by an suitable means, suchas the upper and lower forwarding rollers 40 and 4-2 shown in Fig. l. Inthis arrangement, the forwarding rollers propel the sheets toward theimpression cylinder 16 between upper and lower generally horizontalguide plates 44 and as. The sheets are directed toward the impressioncylinder 16 in a generally horizontal direction so that the sheets willreach the cylinder 16 at a point somewhat below the nip betwen theblanket and impression cylinders 14 and 16.

The operation of the gripper mechanism 18 is timed so that the grippers28 are open fully, as shown in Fig. 3, when the sheets are fed to thecylinder 16. In order to insure accurate positioning of the leading edgeof each sheet, the gripper mechanism 18 is provided with stop means 50which are carried by the gripper shaft 38 and are rotatable with thegripper blades 28. The illustrated stop means 50 comprise a plurality ofstop fingers or blades 52 which extend generally at right angles to thegripper blades 28. The stop blades 52 intersect the plane defined by theundersides of the gripper fingers at points spaced inwardly a shortdistance from the ex-- treme outer ends of the gripper fingers 28. Thus,the

' gripper fingers 28 have portions 54 which extend outwardly beyond thestop fingers 52, while the stop fingers '2 have portions 56 which extendupwardly between the gripper fingers 28. The stop fingers or blades 52have shoulder portions 58 which face upwardly under the gripper fingers28 and are adapted to be engaged by the ,un dersides of the gripperfingers when the grippers are open, as shown in Fig. 3. r

In the illustrated construction, the stop fingers or blades are formedon a single sheet metal member 68 which is generally angle-shaped incross section. Thus, the member 60 has two flanges 62 and 64 which aregenerally at right angles to each other. All of the stop fingers 52 areformed on the angle 62. The flange 64 is clamped or otherwise secured tothe gripper shaft 38.

it will be seen that the shaft 30 has a fiat face 66 which isdiametrically opposite from the hat face The bolts 38 may be employed toclamp the flange 6-4 against the flat face 66 of the shaft 38. Thus, theflange 6d extends generally parallel to the gripper blades 28, while theflange 62 extends upwardly toward the gripper blades, generally at rightangles thereto.

It will be seen that a crotch 70 is defined between the outer portions54 of the gripper blades 28 and the stop fingers 52. in order to guidethe leading edge of each paper sheet into the crotch 70, the stopfingers 52 are provided with sheet-guiding elements 72 which extenddownwardly from the plane defined by the undersides of the gripperblades 28. The sheet guiding elements 72. angle outwardly, with respectto the stop fingers 52, and extend at an acute angle to the outerportions 54 of the gripper blades 28. In this case, the sheet guidingelements 72 are formed as tongues struck out of the angle member 60 onwhich the stop fingers 52 are formed. Because of the outward angling ofthe sheetguiding tongues '72, the paper-receiving crotch 78 is acutelyangled.

As already indicated, the sheets may be fed horizontally to theimpression cylinder 16 at a point somewhat below the nip between theblanket and the impression cylinders 14 and 16. The leading edge of thesheet strikes the sheet-guiding tongues 72 somewhat below the outerportions 54 of the gripper fingers. Because of the outward angling ofthe tongues 72, the edge of the sheet is deflected upwardly along thetongues and into the crotch'7-0. Thus, the position of the sheet ispositively and accurately determined by the crotch 7th. As the grippers28 close, the leading edge of the sheet remains in the crotch. Thus, thesheets are positioned peripherally with respect to the impressioncylinder 16 with a high degree of accuracy and reproducibility.Accordingly, the

registration of the printed matter with respect to the head of the sheetis maintained and controlled with great accuracy.

It has already been indicated that the gripper blades 28 are openedfully (Fig. 3) to receive the paper sheets and then are closed to clampthe successive sheets against the anvil portion 24 so that the sheetswill be carried through the nip between the blanket and impressioncylinders 14 and 16 (Fig. 4-). The grippers 28 are then openedsufliciently to release the sheets, as shown in Fig. 5.

These movements are imparted to the grippers 28 by an operatingmechanism '76 (Figs. 2 and 6). In the illustrated mechanism, a pinion 78is secured to the gripper shaft 30 and is arranged to mesh with a sectorgear 80 formed on a lever 81 which is swingable about a pivot 82 on thecylinder 16. A coil spring 84 is tensioned bctween the sector gear lever81 and a cam follower arm 86 which carries a roller 88 adapted to engagea cam 96. In this case, the cam 98 is stationary while the cam followerarm 86 rotates with the impression cylinder E6. The cam 90 is secured tothe mechanical frame. A coil spring 94 is tensioned between the camfollower arm 86 and an anchor 96 on the cylinder 16 so as to bias theroller 88 against the cam 98.

The cam follower arm 86 is adapted to be swung coun- A terclockwise bythe positive action of the cam 90, while being swung clockwise by thespring 94. When the cam follower arm 86 is swung counterclockwise oroutwardly, the spring 84 tends to swing the sector gear lever 81counterwise so as to close the grippers 28.

The cam follower lever 86 may also impart clockwise motion to the sectorgear lever 81 by virtue of a one-way lost motion connection 96, betweenthe arm 86 and the lever 81. It will be seen that the lost motionconnection 96 comprises relatively adjustable, interengageable stopelements 98 and 100 on the lever 81 and the arm 86. In this case, thestop 98 takes the form of an adjustable screw, while the stop 100comprises a flange or lug on the arm 86 and adapted to be engaged by thescrew 98.

The counterclockwise or closing movement of the sector gear lever 81 islimited by relatively adjustable stop elements 102 and 104 on the lever81 and the cylinder 16. In the illustrated arrangement, the stop 102comprises a flange or lug on the lever 81, while the stop 104 takes theform of an adjustable screw carried by the cylinder 16.

In the illustrated case, the gripper cam 90 has a low portion 106adapted to permit the spring 94 to open the grippers 28. When the roller88 engages the low portion 106, the spring 94 swings the arm 86clockwise or inwardly. The interengaging stop elements 98 and 100 swingthe gear sector clockwise, with the result that the pinion 76 and thegrippers 28 are swung counterclockwise to their open position.

The cam has a high portion 108 adapted to close the grippers 28. As theroller 88 passes over the high portion 108, the arm 86 is swungcounterclockwise or outwardly. The spring 84 swings the gear sector 80counterclockwise so as to rotate the grippers 28 clockwise toward theanvil portion 24 on the cylinder 16. To provide firm clamping pressurebetween the gripper blades 28 and the anvil portion 24, so that thesheets will be securely clamped therebetween, the gripper shaft 30 maybe rotated clockwise sufiiciently to flex the gripper fingers 28, asillustrated in Fig. 4. The gripper closing movement of the sector gearlever 81, and hence that of the gripper shaft 30, is limited bytherelatively adjustable stops 102 and 104 on the lever 81 and the cylinder16. Thus, the position of the adjustable stop screw 104 determines theextent to which the grippers 28 are flexed. During the closing of thegrippers 28, the oneway lost motion connection 96 permits overtravel ofthe cam follower arm relative to the gear sector lever 81. Suchovertravel causes the stop flange to move away from the stop screw 98.At the same time, the spring 84 is stretched.

The cam 90 has a portion 110 of intermediate height, extending for themajor portion of the periphery of the cam. The height of the portion 110is such as to open the grippers 28 partially, so as to release theleading edge of the sheet, as shown in Fig. 5.

The released sheet is pushed away from the anvil portion 24 on theimpression cylinder 16 by ejector means 112 taking the form of aplurality of ejector fingers 114 formed on a member 116 which isrotatable independently of the gripper shaft 30, but about the sameaxis. A cam follower arm 118 is mounted on the member 116 and isprovided with a roller 120 which is engageable with a cam 122. The arm118 rotates with the cylinder 16, while the cam 122 is secured to thecylinder shaft 92 and is essentially stationary. A coil spring 124 isstretched between the arm 118 and an anchor 126 on the cylinder 16, soas to hold the roller 120 against the cam 122.

The earn 122 has a high portion 128 adapted to swing the arm 118 and theejector fingers 114 in a counterclockwise direction, so that the ejectorfingers will push the leading edge of the sheet away from the anvilportion 24, as illustrated in Fig. 5. The ejector fingers 114 aremovable through some of the slots 26 in the anvil portion 24. Morespecifically, the ejector fingers 114 and the sheet-guiding tongues 72are positioned alternately in the slots 26.

The ejector cam 122 has a low portion 130 which extends for the majorpart of the periphery of the cam and permits the spring 194 to move theejector fingers 114 to their retracted position, as shown in Fig. 4.

It will be apparent from Figs. 7 and 8 that the ejector fingers 114 arealignedwith the gripper fingers 28, or, in other words, are positioneddirectly under the gripper fingers. The ejector fingers 114 are movablethrough slots 132 defined between the stop fingers 52.

The operation of the gripper mechanism may be summarized by again notingthat the sheets to be printed are fed toward the impression cylinder 16so that they will engage the sheet-guiding tongues 72 which arerotatable with the grippers 28. The underside of the sheet makes anacute angle with the sheet-guiding tongues 72. Thus, the sheet isdeflected upwardly so that it will slide along the tongues 72 into thecrotch 70 between the stop fingers 52 and the outer portions 54 of thegrippers 28. Thus, the acutely angled guiding tongues 72 insure that thesheet will be positively located in the crotch 70. The forwardingrollers 40 and 42 may be arranged to propel the sheet to a slightlygreater extent than is normally necessary to seat the leading edge ofthe sheet in the crotch 70. The overtravel of the sheet is taken up byslight buckling of the sheet.

The grippers 28 are closed as they travel with the cylinder toward thenip between the blanket and impression cylinders 14 and 16. The closingmovement of the grippers 28 is brought about by the high portion 108 ofthe .cam 90, which swings the cam follower lever 86 counterclockwise.The spring 84 imparts corresponding counterclockwise movement to thegear sector 80. Asa result, the pinion 78 and the grippers 28 are swungclockwise. In this case, the sectorgear 80 has a considerably greaterradius than the pinion 78, with the result that the movement of thegrippers 28 is magnified with respect to the movement of the sector gear80. The grippers 28 clamp the leading edge of the sheet against theanvil portion 24, as shown in Fig. 4. In order to flex the gripperfingers 28 and thereby provide for firm clamping pressure between thefingers and the anvil portion 24, the gripper shaft 30 may be rotatedslightly beyond the portion in which the gripper fingers move intoclamping relation with the sheet. Such overtravel of the gripper shaft30 is controlled by the adjustable stop screw 104, which limits thegripper closing movement of the sector gear lever 81. Any additionalovertravel of the cam follower lever 84 results in separation betweenthe stops 98 and ltl'h and stretching of the spring 84.

After the'grippers 28 pass the nip between the blanket and impressioncylinders 14- and 16, the roller 88 encounters the intermediate portion110 of the cam 90, with the result that the spring 94 swings the camfollower arm 86 clockwise. The stops 98 and 100 transmit the clockwisemovement to the sector gear 80. Accordingly, the grippers 28 are swungcounterclockwise away from the anvil portion 24, as shown in Fig. 5.

The high portion 128 of the ejector cam 122 swings the arm 118 and theejector fingers 114 counterclockwise so that the fingers will push theleading edge of the sheet outwardly away from the cylinder 16. The sheetis then pealed off the impression cylinder 16 by stationary stripperelements 134 (Fig. 2).

As the grippers 28 approach the position in which the paper is fed tothe cylinder 16, they are opened fully by the engagement of the roller88 with the low portion 106 on the cam 90. The spring 94 swings the arm86 and the sector gear 80 in a clockwise direction, so that the pinion78 and the grippers 28 will be rotated counterclockwise. Thus, thesheet-guiding tongues 72 on the stop fingers 52 are swung outwardlybeyond the periphery 6 of the, cylinder 16 so that the paper sheets willimpinge upon the guide tongues 78 as the sheets are fed toward thecylinder 16.

It will be appreciated that the gripper construction of the presentinvention is eflective and dependable in operation, yet is reasonablysimple and low .in cost. The angularity of the guide elements carried bythe grippers insures that the leading edges of the sheets will beproperly positioned relative to the printing cylinder.

Various modifications, alternative constructions, and equivalents may beemployed without departing from the true spirit and scopeof theinvention as exemplified in the foregoing description and defined in thefollowing claims.

We claim:

1. In a printing machine, the combination comprising a printing cylinderhaving a cylindrically curved surface portion for receiving a sheet tobe printed, an anvil portion extending longitudinally of said cylinderadjacent one end of said surface portion, a gripper shaft rotatablymounted on said cylinder adjacent said anvil portion, said shaft havingdiametrically opposite flat faces thereon, a plurality of flat springsheet metal gripper blades fixed on said gripper shaft against one ofsaid faces and having outer end portions swingable into and out ofengagement with said anvil portion for clamping a sheet therebetween, anangle shaped stop member having a pair of flanges thereon extendinggenerally at right angles to each other, one of said flanges being fixedto said gripper shaft against the opposite flat face thereon, said oneflange extending from said shaft under said gripper blades and generallyparallel thereto, the other flange on said stopmember having notchestherein receiving said gripper blades and portions defined by the saidnotches and extending between said gripper blades generally at rightangles thereto, said stop member having a plurality of sheet guidingtongues struck therefrom and extending outwardly from said other flangeand downwardly relative to said gripper blades at an acute anglethereto, said tongues defining an acutely angled crotch between saidtongues and said gripper blades for receiving and positioning theleading edges of the sheets to be printed.

2. In a printing machine, the combination comprising a printing cylinderfor receiving successive sheets to be printed, said cylinder having ananvil portion against which the leading edge of each sheet is adapted tobe clamped, a gripper shaft rotatably mounted on said cylinder adjacentsaid anvil portion, a plurality of flat, flexible, resilient gripperfingers secured to said shaft and swingable into and out of engagementwith said anvil portion for clamping the leading edge of each sheettherebetween, a plurality of stop fingers secured to said shaft andextending between said gripper fingers generally at right anglesthereto, a plurality of sheet-guiding elements fixed on said stopfingers and extending downwardly from the underside of said gripperfingers, said gripper fingers having outer portions extending beyondsaid stop fingers, said sheet-guiding elements on said stop fingersextending at an acute angle to said outer portions of said gripperfingers and defining an acutely angled crotch therebetween for receivingand positioning the leading edge of each successive sheet to be printed,a pinion secured to said gripper shaft, a gear sector meshing with saidpinion and mounted on said cylinder for swinging movement about apredetermined axis, a nonrotatahle cam coaxial with said cylinder, a camfollower arm swingable on said cylinder about said predetermined axisand having a roller engageable with said cam, a first spring connectedbetween said cylinder and said cam follower arm for biasing said rolleragainst said earn, a second spring connected between said follower armand said gear sector and operative to swing said gear sector in a firstdirection in response to outward movement of said follower arm by saidcam, said movement 'of said gear sector in said first direction beingoperative to swing said gripper fingers against said anvil portion, saidsecond spring being yieldable to provide for outward overtravel of saidcam follower arm, relatively adjustable stop elements on said cylinderand said gear sector for limiting movement of said gear sector in saidfirst direction, and relatively adjustable stop elements on saidfollower arm and said gear sector for swinging said gear sector in asecond opposite direction in response to inward movement of said camfollower arm for swinging said gripper fingers away from said anvilportion.

3. In a printing machine, the combination comprising a printing cylinderhaving a cylindrically curved surface portion for receiving a sheet tobe printed, an anvil portion extending longitudinally of said cylinderadjacent one end of said surface portion, a gripper shaft rotatablymounted on said cylinder adjacent said anvil portion, a plurality offlat spring sheet metal gripper blades fixed on said gripper shaft andhaving outer end portions swingable into and out of engagement with saidanvil portion for clamping a sheet therebetween, a stop member fixed tosaid gripper shaft and having a flange thereon with notches thereinreceiving said gripper blades and defining finger portions extendingbetween said gripper blades generally at right angles thereto, said stopmember having a plurality of sheet guiding tongues struck from saidfinger portions and extending outwardly therefrom and downwardlyrelative to said gripper blades at an acute angle thereto, said tonguesdefining an acutely angled crotch between said tongues and said gripperblades for receiving and positioning the leading edges of the sheets tobe printed.

4. In a printing machine, the combination comprising a printing cylinderfor receiving successive sheets to be printed, said cylinder having ananvil portion against which the leading edge of each sheet is adapted tobe clamped, a gripper shaft rotatably mounted on said cylinder adjacentsaid anvil portion, a plurality of flat, flexible, resilient gripperfingers secured to said shaft and swingable toward and away from saidanvil portion for clamping the leading edge of each sheet therebetween,a plurality of stop fingers secured to said shaft and extending betweensaid gripper fingers generally at right angles thereto, a plurality ofsheet-guiding elements fixed on said stop fingers and extendingdownwardly from the level of the underside of said gripper fingers, saidgripper fingers having outer portions extending beyond said stopfingers, said sheet-guiding elements on said stop fingers extending atan acute angle to said outer portions of said gripper fingers anddefining an acutely angled crotch therebetween for receiving andpositioning the leading edge of each successive sheet to be printed.

5. Ina printing machine, the combination comprising a printing cylinderfor receiving successive sheets to be printed, said cylinder having ananvil portion against which the leading edge of each sheet is adapted tobe clamped, a gripper shaft rotatably mounted on said cylinder adjacentsaid anvil portion, a plurality of gripper fingers secured to said shaftand swingable into and out of engagement with said anvil portion forclamping the leading edge of each sheet therebetween, stop means securedto said shaft and extending transversely to said gripper fingers todefine a crotch therebetween for receiving and positioning the leadingedge of each successive sheet to be printed, a pinion secured to saidgripper shaft, a gear sector meshing with said pinion and mounted onsaid cylinder for swinging movement, a no-nrotatable cam coaxial withsaid cylinder, a cam follower arm swingable on said cylinder and havinga roller engageable with said cam, a first spring connected between saidcylinder and said cam follower arm for biasing said roller against saidcam, a second spring connected between said follower arm and said gearsector and operative to swing said gear sector in a first direction inresponse to outward movement of said follower arm by said cam, saidmovement of said gear sector in said first direction being operative toswing said gripper fingers against said anvil portion, said secondspring being yieldable to provide for outward overtravel of said camfollower arm, stop elements on said cylinder and said gear sector forlimiting movement of said gear sector in said first direction, and stopelements on said follower arm and said gear sector for swinging saidgear sector in a second opposite direction in response to inwardmovement of said cam follower arm for swinging said gripper fingers awayfrom said anvil portion.

References Cited in the file of this patent UNITED STATES PATENTS1,609,601 Berry Dec. 7, 1926 2,599,776 Peyrebrune June 10, 19522,647,462 Dell Aug. 4, 1953 2,720,165 Gullixson Oct. 11, 1955

